Single-stroke-heading machine



Feb.- 22 1927.

J. KUH

SINGLE STROKE VHIEADIM': MACHINE Filed Jan. 28. 1924 W//y 1i 4 L t l jew Figg P W T111 ai. r I k m g1 d g b h u f K `5,; mL i1 F1' g'.3

, ai k m a f l g b l h I; E mi n P |11 4 k m 12J/en for 3 uNiTlazD sra'rris lmarlN'rlv OFFICE.

. .'Tosnrrr KUHNE, or Isra-norm, GERMANY.

lsrrrcfnn-srnoxn#rmnnrue MACHINE;

Application led January 28, 1924i, Serial No. 689,200, and in Germany .Tune 26, 1922.

operative stroke'of the reciprocating header slide, duringthe first part of which stroke the operative pressure is applied only upon the normal cross-section of the blank, guided within the movable header part, to compress` and express the exposed portion of the blank to form a preliminary head, and during the latter part of which operative stroke the upsetting pressure is extended ove-r the primarily formed head to spread it yout further and complete the heading operation.

The specific method of upsetting the blank by the present mechanism is described in my co-pending application, Serial No. 12,377, filed February 28, 1925. y f

My invention will best be understood when described in connection with the accompanying drawing, in which Fig. 1 is a' longitudinal section through the lmprovement, with the partsI in their relative position just prior to the beginning of the presv sure stroke; Figs. 2 and 3 are similar sec-'"' tions with the parts at intermediate operative stages, and Fig. 4 shows the termination of the pressure stroke.

The stationary, axially perforated die a is rovidedwith the matrix a1 of the size an shape of the lower portion of the'head to be formed. In the head block b of the reciprocablepressure slide o, forming part of a suitable heading or upsetting machine, 1s secured bymeans. of the set screw d a sleeve f in which the plunger g is reciproup. In the bore i is reciprocably guided a pressure rod or punch lc, the vrear endof which bears against the reduced portion m of the stepped uthrust `member, m-mf-/n whose rear portion 'a cont-acts with the ad- .justable Wedge member o in the-,reciprocablepressure slide c. The punch k and the thrust member n., m together constitute the preliminary stamping punch and in later coaction with the plunger g serve as final heading member, the plunger in its front face showing the replica of the top conforv mation'ofthe finished blank head.-

The co-operation of the described parts vis as follows: The stock blank p is fed in well known manner through the central bore in the stationary die a until it projects an amount corresponding to the. volume of the head to be formed. AThe pressure slide c is now advanced in suitable manner the bore i of plunger g engaging `over the protruding portion of the blank p (Fig. 2). On cony tact with the stationary die a the plunger g is checked in its advance and closes the matrix a forl the first forming operation, but the member acontinues its forward pressure movement and the blank materiall embraced by'the plunger head is compressedand forced out of the latters bore el by the punch lo and' into the matrix a where it spreads out, as shown in Fig. 3to form an i'nchoate head, the plunger g receding within the steadily advancing header block b under compression of the spring L so that its forward shaping end moves away from the matrix to such an extent as to allow the inchoate head to be formed and to project partially beyond the face of the matrix. By this means an Iamount of metal may be upset in this preliminary operation suficient to form a complete head of the desired large diameter when flattened out by the second upsetting action into finished form. Finally, when the front edge of the punch k reaches a positiony flush with the front edge of the plunger g, the inner annular extremity gL of the latter is engaged by the shoulder m1 of the member m, with the result that, on further advance ofthe slide c, the plunger g and the punch lc, are together positively advanced in relative' immovability toward the die a so as to conjointly form a finishis finally compressed and shaped to a finished ,i'ng patrix die, whereby the inchoate head.-

form, as Shown in Fig. 4. The pressure slide c is then retracted and the headed article pushed out of the die a and cut off in suitable, well known manner.

The tension of the coil spring z, is so adjusted that it readily allows the plunger g to recede a relatively slight distance away from the stationary die a upon the blank material being crowded in between the matrix and the complemental plunger depression (Fig. 3), whereupon the shoulder m1 of the still advancing punch member c, m immediately contacts with the inner plunger edge g1, forcing the plunger into its final heading position (Fig. 4).

The advantages of a machine operating as above described over prior machines and method are, briefly stated, as follows: In making headed articles of the character set forth, two general processes are commonly employed. In one of these processes the stock is heated and upset while in a heated state. Articles so made possess the requisite strength, but the cost of manufacture isl comparatively great because of the necessity of preliminarily heating the stock. In the other of these processes, commonly known as the cold process, the blank is upset in an unheated state in two stages, when a largesized head is to be formed, i. e., by successive upsetting or swaging actions. These actions are performed by a so-called doubler pressure press in which,`on one stroke of the press, a plunger acts to force an enclosed end of the blank projecting beyond the 'matrix back into the matrix to form an inchoate head, and on a second stroke of the machine a second plunger acts to press the inchoate head into finished head shape. Such double-pressure presses, as heretofore constructed, are cumbersome and clumsy in construction, requiring the use of shifting means to successively dispose the plungers at different levels for Working actions, tthey are slow in action because two working motions or cycles are required for the production of each article, and they are defective in operation because of.an inherent fault due to the fact that a measurable time interval occurs in the action upon the blank of the two working punch members. When the first punch member exerts its working pressure on the blank a certain amount of heat is generated in the blank. I have discov ered 'that thls amount of heat is sufiicient to cause the metal to fiow readily under a succeeding pressure if the metal is again acted upon in due time, i. e., before the heat comes to the surface, but that, unless the second pressure is immediately applied, the `engendered heat passes to the surface of the blank and is given off, allowing the blank to chill and cool. This chilling or cooling of the blank is undesirable, for the reason that, if the second pressure is applied after chillbreak off upon a mere tap being given them,

so that the additional and costly operation of annealing must be resorted to in order to produce bolts of proper strength. All prior double-liu'essure presses with which I am familiar have this faulty action because' of the time interval ensuing between the operation of the punches, the stock chilling and cooling offafter the first pressure is applied to form the inchoate ,head and before the second pressure can be applied to complete or finish the head.

By the use of the method of operation employed by my machine the expense of heating the blank prior to upsetting, as in the heat swaging process, and the abovenoted objections to the two-stage cold swa ing process heretofore in use, are whollyl overcome. In the operation of my machine, the instant the'pressure stroke of the first pressure plunger is completed, the second pressure plunger g comes into action, the

two plungers then moving together as a unit coaxially, whereby immediately upon the formation of the inchoate head b the plunger la both plungers work toget er to conjointly apply their pressures over the full area of the inchoate head to Hatten out the same into finished head form. These successive actions are so timed, and are so rapid, that before the heat in the inchoate head engendered by the stroke of plunger vla can come to the surface, and while the metal of the inchoate head is still therefore in a more or less fluent or plastic state, the plunger q comes into action with the plunger and the forces of both plungers are applied at a time when the material will readily and easily flow from one formation into the other, so that no cooling or other undesirable structural changes in the material can take place during the time period of thev formation of the complete head. Headed articles having superior strength are thereby produced from cold stock without annealing or other further treatment. Furthermore, my construction, admitting of the use of plungers operating in the manner described, enablesl a 'simple type of machine to be employed which dispenses with the use of time and power consuming mechanisms for shifting successively acting punches into and out cfa proper working plane for action on the blank, and which, at the same time, provides a double-swage action machine in which the swaging actions are, to all intents and effects, continuous with each other and on a single continuous working stroke of the punches, whereby desirable and important advantages are gained,

n die with its axial feedingbore may be replaced by a type of die into which the blank is fed from in front or from the side without in any way altering vthe construction, arrangement and cooperation of the described parts forming my invention.

What I claim is r 1. In aheading apparatus of the character described, a head-forming matrix, a press-slide movable toward and from the matrix, a hollow die member` carried by the press-slide and adapted on a preliminary forward movement of the press-slide toreceive and enclose an end portion of the stock projecting beyond the matrix and to abut against said matrix and to be limited in4 further forward movement thereby, a second die member connected to and positively movable with the press-slide, said second die member having a plunger portion movable in the hollow die member on a further forward movement ofthe press-slide. to displace said projecting end portion of the stock from the hollow die and preliminarily upset the same in the matrix, the .degree of forward movement of said second die on such preliminary upsetting motion being such as to bring the front ends Aof the two die members into coacting relation to form a unitary die surface for a unitary final upsetting'` action of both die members on the preliminary upset portion ofthe stock, means for yieldingly backing the hollow ,die member and` yieldingly coupling said die members to permit said second die member to have forward movement independent of the hollow die member for `its stock-end displacing and preliminary upsetting action, and means -f'or positively coupling said die members for a joint forward final upsetting `.motion on the completion of said preliminary upsetting movement of the second die member.

2. In a heading apparatus of the character described, a press-slide, a' hollow die member for enclosing the end of the stock to be upset, said die member being guided for limited longitudinal movement in said press` slide, a stationary head-forming matrix serving as a stop for limiting the forwardmovement of said hollow die member in the forward movement of the press-slide, a second die member for pressing said stock-end out of said hollow diemember into said matrix, said second die .member being guided in said hollow die Amember and engaged with the press-slide rfor positive motion therewith, a spring fory yieldingly coupling said die members and permitting forward movement of the second die member independent of the hollow die member when the forward movement of the latteris arrested,

and a shoulder on said second die member for positively cou ling said second die member and said hol ow die member, said die members, after being positively coupled, conjointly forming a final upsetting die.

3. In a heading apparatus of the character described, a head-forming matrix, a press-slide,v a hollow die member for enclosing the end of the stock to be upset, said die member being slidably mounted in said press-slide and adapted to abut against the matrix on a preliminary portion of the forward movement of the press-slide so as to laterally close the matrix and to be limited in its forward movement thereby, a second die member for pressing said stock-end out of said hollow die member into said headforming matrix and preliminarily upsetting the same therein, said second die member being guided in said hollow die member and engaging said press-slide for positive movement thereby, resilient means for coupling said die members in the direction of their' forward stroke, said resilient means permitting the press-slide and second die member to move forward after the hollow die inember -abuts against. the matrix until the said second die member forces thev projecting stock-end into the matrix and then permitting the hollow die member. to recedeA under pressure from vsuch preliminarily. upset stock-end to such a position that the distance.V i

between the bottom` of lthe Ahead-forming matrix and the front face of saiddie mem ber is greater than the finishedl height vof the head to be formed, and a shoulder on said second die member adapted to abut against the rear `end of said hollow die memberk for positively coupling said die members for a linal unitary wforward motion when the preliminary upsetting of the.

stock end is completed, the length of that portion 'of said 'punch which lies in front of said shoulder being such that the front tive coupling takes place, coact to form together a finishing die surface to Hatten out and complete the formation of the head.

4. In .a heading machine, a matrix, a press-slide movable toward `and from the matrix, inner' and outer coaxial] movable dies carried by the slide, one die eing slidably mounted in the press-slide-and operative on a predetermined forward movement of said press-slide to enclose a portion of a `stock blank projecting beyond the matrix faces of said die members, when such posino.

ously bring the die faces of the two dies into position to form a unitary die surface, and said dies bein movable in unison on a. continued forwar movement of the prsslide and at the completion of the sald inchoate head forming action to causel their die faces to compress and flatten out the in- Choate head in the matrix into finished head form,""and coupling means for controlling and cooperatively connectin said dies for 10 such working actions on eac forward singie stroke motion of the press-slide.

In testimony whereof I aix my signature.

JOSEPH KUHNE. 

